Site-built laminated (gluelam) beam

[JohnnGA]

I am planning on replacing two 8' wide side-by-side (with appx. a 3'wide wall section between them) garage doors with a single 16' wide door. I know I could buy a gluelam type engineered beam for a header over the opening, but for several reasons would rather not.
Is there any reason I can't glue and nail together a laminated beam in place over the door opening? This would follow gluelam type construction; 2X4's laid flat and glued and nailed together.  Would it be better (ie stronger) than a double 2X12 glued and nailed to 1/2" plywood in the center?
Any thoughts, ideas or advice will be appreciated.

[glenn-k]

I don't get that deep into it myself, John.  Glulams, I guess would be considered an engineered wood product, but it seems if you came up with a method that made a beam that was as strong it should work.  

Here is a photo of a 16' box beam design using 2x4's and 1/2" plywood from an old book I have.



8' and 8' plywood front side - 4' 8' 4' back side to stagger all joints -- double top flange - double bottom flange shown in detail picture - I'd glue all joints as well as nail them -- calls for 10d nails in 2x4s and 8d nails for nailing plywood on. 2x4 stiffeners on 48" centers to be under splices.

Height is 16"

I don't know if this would be accepted by local inspectors or not -- they would probably want to see a regular or engineered beam.

[peg_688]

 #1:   I know I could buy a gluelam type engineered beam for a header over the opening, but for several reasons would rather not.

 #2:     Is there any reason I can't glue and nail together a laminated beam in place over the door opening?


 #3:     Would it be better (ie stronger) than a double 2X12 glued and nailed to 1/2" plywood in the center?
   

          Any thoughts, ideas or advice will be appreciated.

 #1:   What would be the reason's to make your own? Free lumber, free glue , the challange ?

 #2: If it need's to meet code a site built glue lam out of 2x4 on the flat would not pass. To many variables , no eng. stamp rating etc .

#3: I guess it could be stronger , IF we knew all the variables , grade of lumber / type , moisture content (this would effect what ever glue you intended to use ), type glue you'd use .

 As some glue's "creep" under load , epoxy is very moisture "sensitve ", some glue's fall castrophly under load , etc.


 So IT DEPEND's , there are to many variable's in your question . What  is the load above ? Gable end , rafter's , floor joist's

 The dbled 2x12 with ply core MTL is more than enought , the glue in that case would not be a factor to a inspector , just nail it


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           3    2   3    2   3     2   3  

      about 16" OC between the row of 3  , the row of 2 centered on that .

 From both side'd , off setting  the nail pattern mainly so the nail's don't hit each other as often.

 If it was me,  I'd buy the glue lam or LVL .   All the work to lam your own is a re- invention of the wheel.

 G/L PEG

   

[bil2054]

JohnGA, the other day I read an article about headers by one of the contributing editors of "Fine Homebuilding Magazine".  He said pretty much the same thing as PEG.  The one difference is he uses foam insulation board instead of plywood.  He says the plywood is just there to bring the header flush with the framing, which the foam board does while also acting as a thermal break.
Another guy in the same book builds headers the way Glenn wrote about.  I would lean towards PEG's solution, I think, because I can look it up in a span table. Unless I had an engineered design for the particular application, I wouldn't trust my work.[smiley=undecided.gif]
Still a third guy bangs the 2" bys together, and puts the foam layer on the inside face of the header.
None of 'em bothers about glue in this application; I guess it hasn't enough added value to justify the expense and time.
By me it would be easiest and quickest to go the 2"x12" sandwich route.
Good luck with the project.